Projectile with high initial velocity



Nov; 18, 1969 F'. R. THOMANEK ET AL 3,478,685

PROJECTILE WITH HIGH INITIAL VELOCITY Filed Jan. 26. 1968 INVENTORS 2 Heinz Schlesiger Franz R.Thomunek by WWW W ATTORNEYS United States Patent PROJECTILE WITH HIGH INITIAL VELOCITY Franz Rudolf Thomanek, Landkreis Schrobenhausen,

Upper Bavaria, and Heinz Schlesiger, Schrobenhausen,

Upper Bavaria, Germany, assignors to Bolkow Gesellschaft mit beschrankter Haftung, Ottobrunn, near Munich, Germany Filed Jan. 26, 1968, Ser. No. 700,808 Int. Cl. F42b 3/08 U.S. Cl. 102-24 4 Claims ABSTRACT OF THE DISCLOSURE A projectile with high initial velocity is formed from the conical cavity lining of a relatively static hollow charge during detonation of the charge, and capable of penetrating through a relatively thick camouflage layer, or armor without substantial impairment of its piercing effect. The lining of the conical cavity is an integral conical lining having its portion nearer the axis of the cavity formed with a more acute apex or cone angle than the overall conical angle or pitch angle of the lining. In addition, that part of the lining nearest the axis has a substantially reduced thickness as compared to the remainder.

of the lining. An additional increase in the initial impulse and an increased effect are attained by forming the hollow explosive charge to have an exterior form of a truncated cone.

BACKGROUND OF THE INVENTION In fighting tanks, it is known to use underground mines acting from beneath against the driving gear of the tank or against the bottom armor of the tank when the latter rolls over the mine. Aside from being designed as pure explosive mines, without any piercing effect, the mines can also be designed as shaped or hollow explosive charges. However, the latter have the disadvantage that the barb, formed by the lining of the hollow or shaped charge, makes only a relatively small hole when striking the armor, and then has only a little effect inside the tank.

It has also been suggested to use, for fighting armor cars at long range, hollow explosivecharges where a projectile of high initial velocity is formed, during detonation of the explosive charge, from the lining of a conical cavity having a cone or apex angle of 120460". In contrast'to hollow explosive charges of the conventional type, and known armor-piercing mines, such projectiles may weigh several kg. and attain velocities of 1400 to 2000 m./sec., so that a high piercing effect at close to medium ranges is ensured.

I-Iowever, just like armor-piercing mines and hollow explosive charges, projectiles of-this type have a consider able-loss in effectiveness if they are covered, for reasons of camouflage, with a more or less thick layer of earth. This is due to the fact that a considerable portion of the energy of the explosive charge is absorbed in clearing the camouflage. Although it has already been suggested to remove the 1 camouflage layer by a clearing charge exploded or detonated shortly before the detonation of the main charge, such solutions require considerable expendi tures, inaddition to being unreliable to a certain extent.

I SUMMARY OF THE INVENTION This invention relates to projectile charges having a high initial velocity and, more particularly, to such a projectile charge capable of penetrating or clearing a camou- 3,478,685 Patented Nov. 18, 1969 In accordance with the invention, the lining of the conical cavity is formed as a one piece lining, of suitable metal, with at least' the outwardly facing surface of the lining comprising two coaxial surfaces having different cone or apex angles. That portion of the outer surface of the metal lining of the conical cavity nearer the axis of the lining has a cone angle which is more acute, or less than, the cone angle of the radially outer portion of the outwardly facing surface of the lining. In a hollow explosive charge with its conical cavity lining designed in the manner just mentioned, the lining is deformed, by increasing the impulse or force acting on that part closest to the conical axis, to a projectile having a leading partial projectile. Thus, the part of the lining closest to the axis detaches itself, at a high velocity, from the mass of the projectile proper, due to the higher impulses or forces acting on that part of the lining closer to the axis. This part, which may be called a leading partial projectile,

- axis, and starting from a diameter which corresponds to about the inner third of the outer diameter of the lining, about 90410, when the cone angle of the major or radially outer portion of the lining is from l20l60.

The wall thickness of the lining nearer the base of the cone is made to be from 5 to 10% of the outside diameter 5 of the cone, .whereas the wall thickness of the parts of the lining closest to the axis is made to be from 2.5 to 5% of the outside lining diameter In accordance with another embodiment of the invention, the effect of the invention can be obtained by a lining form which is simpler than that just mentioned. In this other embodiment of the invention, that surface of the lining nearest the explosive charge, or which may be termed the inwardly facing surface of the lining, has a rectilinear generatirix extending from the base to the apex of the cone and corresponding to the generatrix of the conical cavity in the charge. The wall thickness of the lining, in that portion thereof nearer to the axis decreases progressively to the cone apex, starting from a base diameter which corresponds to one-third of the outside of the overall cone. This is effected in such a manner that the wallthickness at the apex of the cone is between 0.5 and 1.5% of the outside lining diameter This decrease in the thickness of the lining in that portion nearest the axis of the cone, of course, results in this portion of the lining having a more acute cone angle than the overall cone angle.

'While, in armor-piercing mines with a substantially cylindrical explosive charge, the effect and the'formation of a leading partial projectile is limited by the particular dimensioning of the lining, an additional increase of the lmpulse, and thus an increased effect, can be attained, in

accordance with another feature of the invention, by an respect to the arrangement and priming of a special clearing charge.

Still another object of the invention is to provide such a projectile including an explosive charge having a conical cavity with a one-piece or integral lining, of metal or the like, in which at least the outer surface of that portion of the lining radially nearer the apex of the cone has a cone angle which is more acute than the overall cone angle of the conical cavity.

A further object of the invention is to provide such a projectile in which the impulse on that portion of the metal lining radially closer to the cone axis is increased to form a projectile having a leading partial projectile by virtue of detachment of that portion of the lining radially near the cone axis from the remainder of the axis due to the increase in the impulse acting on this portion of the lining.

Yet another object of the invention is to provide such a projectile in which that portion of the metal lining radially nearer the axis, and starting from a diameter which corresponds to about the inner third of the outer diameter of the conical recess, has a greatly decreased cone angle compared to the remainder of the lining.

A further object of the invention is to provide a projectile of the type just mentioned in which the wall thickness of the lining at the base of the conical recess is from to of the outer diameter of the base of the recess, with the wall thickness of that portion of the lining radially nearer the axis of the conical recess being from 2.5 to 5% of the outside diameter of the base of the conical recess.

Another object of the invention is to provide such a projectile in which the surface of the lining nearer the shaped charge is generated by a rectilinear generatrix.

A further object of the invention is to provide such a projectile in the form of an armor-piercing mine in which the impulse acting to form the leading partial projectile is increased by forming the exterior surface of the explosive charge as a truncated cone.

BRIEF DESCRIPTION OF THE DRAWINGS For an understanding of the principles of the invention, reference is made to the following description of typical embodiments thereof as illustrated in the accompanying drawings.

In the drawings:

FIG. 1 is a side elevation view, partially in section, of an armor-piercing mine including an explosive charge whose outer surface is substantially cylindrical, and in which the metal lining of a conical cavity is formed by a generatrix having portions extending, relative to the axis, at two different acute angles;

FIG. 2 is a diametric sectional view, on an enlarged scale, of the lining shown in FIG. 1;

FIG. 3 is a view similar to FIG. 1 illustrating a lining in which the generatrix of that surface of the lining nearer the explosive charge is rectilinear, with the portion of the lining nearer the axis having a progressively reduced wall thickness;

FIG. 4 is a diametric sectional view, to an enlarged scale, of the lining shown in FIG. 3;

FIG. 5 is a view, similar to FIGS. 1 and 3 of an armorpiercing mine where an increase of the impulse on that part of the lining nearer the axis is effected by forming the exterior surface of the explosive charge as a frustoconical surface; and

FIG. 6 is a diametric sectional view through a projectile having a high initial velocity and including a leading partial projectile formed in accordance with the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS As seen in FIGS. 1, 3 and 5, an armor-piercing mine embodying the invention comprises a circular cross section explosive charge 1 which has a conical cavity 2 opening in firing direction. Cavity 2 is lined with a metal lining or coat 2 which is substantially conical in form. The lining or coating material used is a known material, preferably a ductile material, for example, carbonfree iron.

As can be best seen from the enlarged diametric sectional view of lining 3 shown in FIG. 2, the lining COnsists essentially of an outer conical part 3a having an obtuse cone or apex angle, and an inner part 3b adjoining the outer part and forming the inner third of the lining. The inner part 3b has a more acute cone or apex angle than does the outer part 3a. Lining 3 is a one-piece or integral lining.

In accordance with the invention, the lining is so designed, with respect to its dimensions, that the cone or apex angle of part 3a of lining 3 is from 120 to 160, and the cone or apex angle of part 3b, which is closer to the axis of the lining, is from to The base diameter of part 3b of lining 3 corresponds to about the inner third of the base diameter or outer diameter of part 3a of lining 3. The wall thickness of the lining at the base of the conical cavity is from 5% to 10% of the outside diameter of the lining, and the wall thickness in the range of part 3b of lining 3, closer to the axis of the conical cavity, is from 2.5% to 5% of the outside diameter of the lining 3.

This design of the lining results in an increase of the impulse or force of the explosive charge on that part 3b of lining 3 closer to the axis of the conical cavity, so that at least a part of the cone 3b breaks off from the main projectile mass proper after detonation of the explosive charge 1, to form a leading partial projectile.

The resultant deformation of the lining 3 to form a projectile having a high initial velocity is illustrated in FIG. 6, which shows the leading partial projectile. In FIG. 6, the projectile mass, or the residual mass of the lining, is indicated at 4, with the bolt being indicated at 5 and the leading partial projectile at 6. The projectile form represented in FIG. 6 corresponds, in principle, to the projectiles possible in all lining designs in accordance with the invention. In accordance with a further feature of the invention, which has not been illustrated, the form of the projectile mass 4 can be influenced additionally by decreasing the wall thickness of the cone from the outside diameter of the lining 3 to the inner third of the diameter.

The armor-piercing mine shown in FIG. 3 has a cavity lining which differs from the cavity lining of FIGS. 1 and 2, and which is shown on an enlarged scale in FIG. 4. Referring more particularly to FIG. 4, the generatrix of that surface 7 of lining 3 facing the explosive charge extends rectilinearly from the base of the cone to the apex of the cone and, in accordance with the invention and in dependence on the composition of the explosive, forms an apex angle of from to The wall thickness of the lining shown in FIG. 4, at the base of the conical cavity, is between 5% and 10% of the outer diameter of the lining, and is substantially uniform from the outer diameter of the lining to about the inner third of the diameter. From the inner third of the diameter, the wall thickness decreases progressively toward the apex of the cone so that the wall thickness at the apex is between 0.5% and 1.5% of the outer diameter of the lining, as indicated at 9.

While FIGS. 1 and 3 show armor-piercing mines with a substantially cylindrical explosive charge, the explosive charge shown in FIG. 5 has its outer surface formed as a frusto conical surface. The lining of the cavity, in FIG. 5, is the same as that shown in FIG. 4. However, instead of this lining form, a lining such as shown in FIG. 2 could be provided in FIG. 5, if necessary, and with the same advantages. The frusto conical design of the exterior surface of the explosive charge 1, as shown in FIG. 5, has, as compared to the cylindrical explosive charges of FIGS. 1 and 3, the substantial advantage of increasing the impulse on the parts of the lining closer to the axis, and thus of increasing the effectiveness of an armor-piercing mine embodying the invention.

What is claimed is:

1. In a projectile formed by deformation of a metal lining of a conical cavity of a relatively stationary hollow explosive charge responsive to detonation of the charge, and wherein the projectile has a high initial velocity: an improved cavity lining, deformable to form a projectile effective against a target arranged in the direction of the cavity axis but outside the normal range of action of the hollow charge, said lining being a onepiece conical lining consisting of two coaxial conical portions in which a major radially outer portion has a cone angle of 120-160" and a thckness of 5-10% of the outside cone base diameter, and a minor central portion adjacent the cavity axis, of at least the exterior surface of the lining, has a cone angle of 90110, a cone base diameter equal to substantially one-third the outside cone base diameter and a maximum thickness of 2.55% of the outside cone base diameter.

2. In a projectile, an improved cavity lining, as claimed in claim 1, in which the exterior surface of said explosive charge is formed as a truncated cone.

3. In a projectile, an improved cavity lining, as claimed in claim 1, in which the interior surface of said lining,

in contact with the surface of the cavity in said charge, is formed by a generatrix extending rectilinearly from the base of the cone to the apex thereof; the thickness of said lining in said minor central portion thereof adjacent the cavity axis, progressively decreasing in a radially inwardly direction with the wall thickness of said lining at the cone apex of said minor central portion being from 0.5% to 1.5% of the outside diameter of said lining.

4. In a projectile, an improved cavity lining, as claimed in claim 3, in which the exterior surface of said explosive charge is formed as a truncated cone.

References Cited UNITED STATES PATENTS 2,629,325 2/ 1953 Sweetman l0224 2,782,715 2/ 1957 Udry 102--24 2,856,850 10/1958 Church et al. 10224 2,974,595 3/1961 Mohaupt 102-2 4 3,224,368 12/1965 House 102-24 FOREIGN PATENTS 1,022,472 12/1952 France. 1,195,641 6/ 1965 Germany.

VERLIN R. PENDEGRASS, Primary Examiner 

